. >> you're going up to a very hostile environment. >> are you ready for that? >> i know i'm ready for that because i've been trained the last five years. >> reporter: baumgartner, a 43-year-old australian and elite sky diver will rise before daybreak and be lifted by a capsule. the assent will take three hours. temperatures will fall as low as minus 70 degrees. once he jump, baumgartner wearing a pressurized suit will be in free fall for five minutes. his top speed could hit 700 miles per hour. he'll become the first human in free fall to break the speed of sound. >> nobody can tell me what happens to the human body in free fall when you supply super sonic speed. >> reporter: joe kitinger has held the skydiving record since 1960 free falling 84 feet up. he's helping to train baumgartner. >> we have better suits and better equipment but the danger is still there. hasn't changed a bit. >> reporter: nasa and the u.s. air force will monitor baumgartner's jump to learn about high altitude limits on the human body. >> are you understandably nervous about that? >> oh,